Five months after two young cousins vanished while riding their bikes, residents of the northeast Iowa, United States, community where they were last seen are anxiously waiting to hear whether two bodies found by hunters are those of the missing girls.

The families of Elizabeth Collins and Lyric Cook were informed that the bodies were discovered on Wednesday(local time) in a wooded area, Black Hawk County sheriff's Captain Rick Abben said. Elizabeth was 8 and Lyric was 10 when they disappeared July 13 near a popular recreational lake in Evansdale, about 150 kilometres northeast of Des Moines.

Abben said the bodies were being sent to the state medical examiner's office for identification. He said he hoped to release more information Thursday afternoon (local time).

"It's definitely not the outcome that we wanted, obviously," said Abben, appearing to fight back tears. He spoke at a news conference in Evansdale, where the girls were being watched by their grandmother when they disappeared.

"This is a difficult thing for us to go through. It's a difficult thing for the community," he said.

In posting on her Facebook page Thursday, Heather Collins, Elizabeth's mother, wrote that the outcome saddened her but that now "we know our girls are dancing up with our saviour."

A message was left with Craig Ceilly, who has acted as the Collins family's media liaison in the past. Abben said the families had requested privacy.

The bodies were found at Seven Bridges Wildlife Area, about 40 kilometres from Evansdale, authorities said. Investigators from several agencies were working in the tree-covered area, which is intersected by the Wapsipinicon River and is popular for hunting and fishing.

"I would call it more of a secluded area," said Bremer County Sheriff Dewey Hildebrandt. "But it does get regular visits from people that like to use the outdoors."

Hildebrandt said investigators from his agency, the FBI and the Iowa Division of Criminal Investigation and others were processing the area as a crime scene and asked the media to stay away.

At the girls' schools, additional counsellors were made available for students and others, said Sharon Miller, the Waterloo schools spokeswoman. Lyric Cook would have been in fifth grade at Kingsley elementary in Waterloo and Elizabeth Collins would have been in fourth grade at Poyner school in Evandsale.

"We're making it available to anyone across our community who feels the need. We want them to know that's available to them," she said.

Iowa Senator Jeff Danielson, a Cedar Falls firefighter, said the case has affected everyone in the area deeply.

He is drafting proposed legislation that would provide faster distribution of information about missing children through law enforcement and social media. Last summer, some family and community members complained about a lack of information about the case.

"We believe that we can speed up the time that the public is aware of an abduction and let them be our eyes and ears in the immediate time frame," he said.

About 70 people attended a Wednesday night prayer vigil at Meyers Lake in Evansdale, where investigators had found the girls' bicycles and a pink purse hours after they went missing. Some were holding out hope that the bodies weren't those of the missing cousins, though others seemed resigned to accept tragic news.

"I don't want to think the worst, but two bodies. It's just really heartbreaking," said Amanda Mulzac, who lives in nearby Waterloo and was among hundreds of volunteers who helped in the initial search. "At their age I was out by myself, but now it's different. Hold your babies close."

Hundreds of volunteers helped investigators to search for girls, traipsing through cornfields and wooded areas in and around Evansdale, a city of 8000 residents. The mayor even joined the search in his private plane.

Days later, an FBI dive team brought in specialised equipment to search the bottom of the lake. Police then classified the case as an abduction.

Investigators had largely been tight-lipped in the months since. An FBI spokeswoman initially said investigators had reason to believe the girls were alive, but other investigators backtracked, saying only that there was no reason to believe the girls were dead.

Authorities had asked hunters to look out for the girls during the deer hunting season.

Jennifer Lancaster, chief law enforcement official for the Iowa Department of Natural Resources in northeastern Iowa, said she believed deer hunters stumbled upon the bodies and reported them immediately.

Investigators have looked into thousands of tips and chased multiple theories in the case.

They looked into Cook's parents, who had criminal records for prior involvement in making methamphetamine. Cook's father, Daniel Morrissey, is being prosecuted for domestic assault and a series of meth and other drug charges, and he backed out of a plea agreement with prosecutors the day before the disappearance. They have denied any involvement.

The region had rallied in support of the girls. Photographs of the cousins seemed to be everywhere in northeastern Iowa: on T-shirts and buttons worn by locals, and on fliers hung on gas station walls and in business windows. Last week, an anonymous donor pledged US$100,000 for information about the girls' whereabouts, on top of the US$50,000 that police had offered.

After Wednesday night's vigil, family friend Sarah Curl said it was a tight-knit, caring community.

"When something happens to one family it happens to all of our families," Curl said. "This could have happened to anyone."